Pajero idle control and ECU

My mechanic tells me that he thinks my ECU is a bit dicky.
My Pajero is 92 model NH series GLS 3.0 litre EFI petrol version which I bought brand when it was brand new, with just under 240,000 km on the clock.

It was fine until about a week ago when all of a sudden and out of the blue the engine started stalling when the engine revs were allowed to drop , the revs would drop right down and the red light would come on and the engine would stall , ie when pulling up .

Until today - when I could finally get the the right end of the queue and my mechanic had a go at fixing the problem , I have been running the vehicle with the throttle pulled out a tad to stop the idle speed dropping below about normal + a few 100 rpm - to ensure the engine didn't stall.

The mechanic tells me he "fixed" the problem but don't know if it'll keep as he thinks the ECU is the problem - he had pulled it out and wiggled the capacitors about a bit to fix the problem - so he thinks the solders have deteriorated.

I have maintained my pride and joy regularly - and yes it's done a few long - long tours (the longest being Port Hedland via Darwin and Cairns back home to Newcastle a few years ago ), and it has from time to time been on Stockton Beach and Hawks Nest Beach and others. So it hasn't been just a town truck.

The mechanic - put the engine onto the tester and didn't find any other issues.

Anyone else had a similar experience with there Pajero's - what's an ECU for NH pajero cost ?

Should take the vehicle the local Mitsubishi service centre and have them check out the throttle position sensor and throttle control soleniod as well as the ECU and replace these.
Anyone got a handle on the cost of these items if they need replacement?

Will a dicky ECU cause damage to the engine ? The fix is not perfect the idle speed still looks a bit erratic, but at least it hasn't stalled yet.

Very disturbing